Proteomic identification of PKC-mediated phosphoproteins in salivary glands of Drosophila melanogaster

Insect molting is a very complicate physiological process initiated by a class of ecdysteroids, mainly 20-hydroxyecdysone (20E). We have previously shown that protein kinas C (PKC) plays an important role in 20E signal transduction pathway in salivary glands of Drosophila melanogaster. In the present study, we identified a set of PKC-regulated phosphoproteins and evaluated their response to 20E stimulation in the salivary glands of Drosophila using proteomic and western blot approaches. Several PKC-regulated phosphoproteins have been shown to be mediated by 20E in a temporal and dose dependent manner. Considering PKC is involved in cellular translocation of ecdysteroid receptor (EcR) and its heterodimer USP as described in our previous work, the present results suggest that the newly identified phosphoproteins may act as apparatuses for translocating EcR/USP in the cells.